package design_pattern.singleton;

public class Singleton3 {
    private static Singleton3 sl3 = null;

    private Singleton3() {}

    public static Singleton3 getInstance() {
        if (null == sl3) {
            synchronized (Singleton3.class) {
                if (null == sl3) {
                    sl3 = new Singleton3();
                }
            }
        }
        return sl3;
    }

}
